Personal watercraft are sometimes designed with a straddle-type seat to support a driver and one or more passengers seated in tandem behind the driver.
Unlike the driver, the passengers on a personal watercraft generally do not have a handlebar on which they must grip to operate the personal watercraft and by the same occasion brace themselves against change of motion induced forces, thus they must attempt to brace themselves against these forces in other ways. In this regard, most personal watercraft are provided with grab handles or a seat strap on the seat for the passengers to grip, as well as foot rests designed to support the lower limbs and provide a third contact point to stabilize the posture. However, as the grab handles need not to be held for the personal watercraft to operate. The passengers often find themselves not holding on anything to maintain their posture on the personal watercraft. Although this practice is acceptable in steady state motion phases of the operation of the personal watercraft, it nevertheless exposes the passengers to the risk of not being able to react timely to the forces induced by a sudden motion change commanded by the driver resulting in an unanticipated imbalance state of the passengers and a possible subsequent fall to the water. This situation is at odds with the driver's desire to use the personal watercraft at its maximum performance potential as when no passenger is present.
In addition, the passengers are less able to anticipate the forces than the driver who is in control of the movement of the watercraft. The passengers may not have advance notice that the driver intends to cause the watercraft to begin moving, change speed or turn. As a result, the passengers may not expect the forces that they will experience due to these actions by the driver. While these forces are varying in magnitude, simply not anticipating them may be enough to cause some unsteadiness. This further decreases the enjoyment of the passengers. With the development of more powerful personal watercraft, and in particular with the use of four-stroke engines in personal watercraft, more torque is generated at low engine speeds, resulting in faster and more sudden acceleration even at the start of the ride.
Therefore, there is a need for a personal watercraft wherein the forces experienced by the passengers during acceleration of the watercraft are controlled.
There is also a need for a method of controlling the forces experienced by the passengers on a tandem personal watercraft during acceleration of the personal watercraft.
There is also a need for a method of controlling the rate of change of the forces experienced by passengers on a tandem personal watercraft.